This report finds high HCV viral load increases risk of transmission of HCV from mother to newborn.

The transmission rate was 7.8% (9/114). I haven't read the article itself but this is not surprising. The risk of transmission in any case including sexual exposure or IVDU exposure ought to be increased if the person with HCV has a higher viral load. This is likely true for HIV as well. Breast feeding had a higher rate of HCV transmission in this study compared to bottle feeding but the authors said it was not statistically significant. I still think breast feeding is a risk. In fact this Rueters report says only mothers with high HCV viral loads transmitted to the baby, suggesting merely having HCV may not create much of a risk factor unless viral load is high. The author suggests testing for HCV and if positive with high viral load, HCV treatment may be appropriate to reduce viral load & as a preventative measure for transmission of HCV to the child.

HCV Viremia at Delivery a Risk Factor for Mother-to-Infant Transmission

WESTPORT, CT (Reuters Health) Feb 21 - The risk of mother-to-infant transmission of the hepatitis C virus (HCV) is associated with the presence of maternal HCV viremia at delivery and a high maternal viral load, according to a report in the January issue of the Pediatric Infectious Disease Journal. Dr. Hitoshi Tajiri, of Osaka University, Japan, and colleagues conducted a prospective study to determine the incidence of HCV infection in infants born to anti-HCV antibody-positive mothers and "to elucidate associated risk factors for transmission." They enrolled 141 mothers and followed 147 neonates for a mean of 18.5 months for serum alanine aminotransferase activity, anti-HCV antibodies and HCV RNA.

The researchers note that 33 infants were excluded from the study because they were followed for fewer than 6 months or were not tested adequately. "Of the 114 infants finally evaluated 9 (7.8%) had detectable HCV RNA," they say.

According to the report, the rate of transmission was not influenced by the mode of delivery or the type of feeding. Eight of 90 (8.8%) infants born by vaginal delivery and 1 of 24 (4.2%) infants born by cesarean section were infected. In addition, 9 of 98 (9.2%) infants who were breast fed and 0 of 16 infants who were formula fed were infected. For both factors, the differences between groups were not statistically significant. The investigators note that "all infected infants were born to mothers who had HCV viremia at the delivery and to those with a high viral load." "If preventive measures are available, such as oral antiviral drugs for HCV-infected pregnant women, then infant-mother pairs at high risk, including high maternal viral load, might be candidates for drug therapy," Dr. Tajiri and colleagues conclude.

Pediatr Infect Dis J 2001;20:10-14.